A three-year study of viable airborne fungi in the North Carolina Zoological Park R.J.R. Nabisco Rocky Coast Alcid Exhibit.

Aspergillosis is a common cause of mortality in captive birds, particularly in recently imported birds or captive chicks and their parents. Use of the Andersen N-6 single-stage viable air sampler in the North Carolina Zoological Park (NCZP) R.J.R. Nabisco Rocky Coast Alcid Exhibit before and after the introduction of birds allowed a unique study of the mycological content of the air in a developing self-contained ecosystem. The Alcid Exhibit had a median count of 17 colony-forming-units (CFU)/m3 of air in comparison to 200-500 CFU/m3 and 1,000-3,500 CFU/m3 reported in human dwellings and the NCZP R.J. Reynolds Forest Aviary, respectively. Cladosporium and Penicillium represented 21.3% and Aspergillus 1.08% of the fungi collected. During the study, no respiratory mycoses were reported in any of the alcids. Continuous high-efficiency particulate air filtration, maintenance of low exhibit air temperatures, and an environment with little residual organic material capable of supporting fungal growth were important factors contributing to low colony counts. All colony counts >100 CFU/m3 in the exhibit were related to the apparent introduction of fungi from outside the facility. A reduction in the number of fungi transported from an external source into enclosed cool-temperature aviaries may be sufficient to avoid outbreaks of aspergillosis.

A comparison of sampling methods for airborne fungal spores during an outbreak of aspergillosis in the forest aviary of the North Carolina Zoological Park.

An outbreak of aspergillosis with the death of six birds in the North Carolina Zoological Park R. J. Reynolds Forest Aviary in the spring of 1993 led to an investigation of the concentration of Aspergillus fumigatus spores in the air. No Aspergillus sp. was found in the facility through use of the drop plate method (gravitometric sampling) along with swab-sampling of selected surfaces within the exhibit and plating of food samples and nesting material onto petri dishes of nutrient media. A number factors that could stress the avian population were identified. These included excessive heat in the upper portion of the aviary due to the failure of an air handling system, a malfunctioning cooling tower, and large numbers of visitors to the facility (an average of 3,500/day). In addition, the outbreak occurred during a period of increased nesting behavior. Sampling of the fungal population of the air was conducted 1 year later, when no disease was noted, to compare the sensitivity of the commonly used drop plate method (open plates of nutrient media) with a volumetric impaction method (Andersen N-6 Air Sampler). The volumetric method delivered quantitative as well as qualitative data and exhibited more sensitivity for fungal spores of size similar to those of Aspergillus sp.